Electrical distribution system



Patented Jan. 22, 1924.

UNITED STATES PATENT OFFICE.

GEORGE A. BURNHAM, OF SAUGUS. MASSACHUSETTS, ASSIGNOR TO SEARS B. CONDIT, JR., OF BROOKLINE, MASSACHUSETTS.

ELECTRICAL DISTRIBUTION SYSTEM.

Application filed January 2, 1920. Serial No. 348,858.

7 '0 aZlw/zom it may concern v Be it known that I, GEORGE, A,.'BURNHA'M, a citizen of the United States, residing at Saugus, in the county of Essex and State of Massachusetts, have invented an Improvement in Electrical Distribution-Systems; of which the 'following is a specification, 1 i

-My present invention relatesto electric distribution circuits adapted :to carry -.rela tively large values of curre-nhsandihas more particularreference to an electric conductor, as a bus-bar, connected with switches'forithe controlled distribution of currentto: a ous. parts of the system; 1 :3; '21;

In adistribution system: for large vahies of current, the buses and 'switches',.iw.hich latter are usually oil-immersed, ariarrariged in proximitylto each-other, and relatively short and hav'y'f-leads areextendeduthere between. 'z- .1.

Due' to the heavy currents carried by the bus-bars, they become appreciably; heated,

which heat may be'augmented by a relatively warm circumambient terhperaturef -and natural heat dissipation fromizthezbussbars, even with a laminated structu're,-is not -suffic'ien-t to maintaina low operatingtemperature, because of i'nsufiicient heat dissipating area.j

The heating and resultant relativelyhig'h temperature of the bus-bar seriously and detrimentally affects the operation of the :oil immersed switches associated therewith. It is essential that the temperature of the oil-immersed switch he maintained at a low value as otherwise the interrupting capacity of the switch will be greatly decreased, or its efiiciency will be reduced and the switch will fail safely to interrupt the current'and protect its circuit. I f The leads connecting the switch with the heated bus-bars, as-previously stated, are relatively massive and are excellent-conductors of heat; and heat of'the bus-bars is conducted through theseconductorsf in'to the switch. The heat of the bus-bars is added to the heat generated in the'switchfitself with the result that the temperature of the switch reaches such a high value that it fails prop erlv to operate.

nv obJect of this invention therefore, is to provide the bus-bars with additional heatdissip-ating area, or with cooling means, whereh to maintain them at. a vrelatively lowan safe operating temperature.

. A further object is to provide the bus-bar with a plurality of independent cooling means arranged along its length in heat-ex- :changing relation therewith, by which heat is conducted along the length of the bus-bars -cationcfiled January 24, 1920, Serial F-ig. l'is a side elevation of a portion of an electrical distribution system, inoludin busbars and an oil immersed switch embo ying my invention." a v ii Fig.2 is a plan view of Fig. -1.

: As h'e're shown the electrical distribution system includes the three parallel distribution conductors or bus-bars 10, for a three {phase system, each formed of a plurality of spacedrapart-bars'mounted upon suitable in- :sulating-supports, as the bracket 11 secured to the back-0f the switch panel 12. l

The bus-bars serve to distribute current from ajcurrent source, not shown, to a pluralityof switches, one of which is here shown as comprising the frame 13 having theoil. recepta le -14: --depending therefrom. rThe switch" i's secured to the back. of said panel "12 below the bus-bars and a switch-operating handle is secured to the front'of the paneL-although the switch may be, and commonly: is, arranged for remote control; in which event the panel will be replaced by other suitable supporting means.

The switch has stationary switch members l5, commonly laminated, which extend from the oil reoeptable, through insulators, above the switch frame, and massive leads 16, also laminated,are secured thereto and extend to, and are connected with the husbars. Said leads, as they are necessarily ood electrical eonductors,'are also excellent eat conductors.

The bus bar cooling means .includesa plurality of independent cooling imitsassociated therewith along its length and, preferably between each switch.

Each cooling unit comprises the independent bus-bar extensions 20 dis osed along the length of the bus-bar. Eac extension is formed of a plurality of strips interwoven with the bus-bar structure and having a suitable extent of heat-dissipating area; and each extension is in ood heat-exchanging relation with the busars. Means are Pl't-H'l-CiB-Cl to artificiallyoool said exten sions I-llGlBbfy' to abstracthcat from the busbars, and the heat. flow is along the bus-bars to the extensions where it is dissipated from the snrfacethereof.

A suitable cooling means may include the receptacle 21 of suitable dimensions mounted on a suitablesnpport 22 extended from the switch panel 12 in proximity to saicHJusbars and adapted to contain an insulating and heat absorbent fluid, as oil, in whic said bus-bar extensions are immersed.

The oil acts to absorb the -heat dissipated by said extensions and thereby to cool the busbacs. The oil is adapted tc be'ma'mtained at a relatively low-temperature as by forming the oil receptacle from' material having good heat condudingpmperties and providing it "with"relatiarelg; greatheat'dissipating surfaces, as b forming at with cooling fins :23 -or:theo1lmny be artificitl ly cooled by circulating therethrou'g'h a cooling medium. For this purpose the oilreceptacle has the cooling coil 25 immersed5' andpref; erably entirely"s1i'bnierged; in the o'il-io'f -the receptacle and spaced from the 'lieat oonducting strips or bus bar extensions QO a'n'd insulated therefrom by the oil. The-cooling coil is included in the circulating system comprising the pump '26; "the mdiator m, and storage tank 28 and' tho orran'gement of the component artsof'*tlie'--systern 'is, preferably such that the direction of flow of hot cooling medium isfrom the cooling coil 25 into the-storage tank, in w'hich'itmay be partially cooled, a:nd"is circulated by the pump 26 througli the radiator'27 and cooled, and again through the cooling coil 25; and abstracts heat from the oil. Tbeaiirection df fiow of the-cold cooling medium in said cooling coil 25 is preferably-in t'lie'tlirection of heatflow in the oil. whichinthis particular instance is upwai'd from 'the hottom of (the oil receptacle 20.

lhe cooling medium may be any suitable Ffiuitl, as watcr, or oil: or the oil in the receptacle 20 be circulated through'thc cooling svstem.

In the operation of this systennheat flows along the bus-bars into the extensions '20 andfis'given up to the oil and lieatiuay'also flow from the switches into the bus-burs and through the bus-bars into the "cooling systom thereby to increase-thecurrent rupturingcapacit'y of the switch! As many units of isolated bus-bar extensions and cooling means therefor will heapplied. to isolated points on thelms-har structure as are found to be necessary, in any par. ticular installation, to adequately cool the d ist-ribution system.

The above described method of cooling the svstem is also adapted to be applied as an attachment to existing systems.

i is Ol)\'-im|$ that many modified arrangemonks may be devised all embodying the spirit of any invention.

I claim 1. An electrical disirihution system in cluding .a conductor of substantial length heated by the current carried thereby, and cooling means therefor comprising a plurality of independent heat dissipating units associated with said-conductor at independent points along its length arranged to abstract heat therefrom and dissipate the heat abstracted.

2. Aneleetricall distribution system com prisin a, conductor of substantial length heat by the current carried thereby. an oil immersed switch electrically and ther mally connected-with said conducbo 'and cooling means for the systemcomp'risilig a plurality of independent cooling units assb- -ciatedwith said conductor along its length to abstract-heat therefrom and -'fro1-n--:the system: i a l 3. An electrical distribution systiem oornprising a conductor of substantiall length, a lurahtysoi isolated moeptacles'alapted to contain an electrically-insulating; meat-dbsorbent'fluid; as oil, said conductor having isolated portions thereof immersed 'in the fluid ilisaid receptacles and-in heat-exchang' ing relation therewith, st-ract heat from and-cool =t he fiuidin said receptacles-whereby to cool said conductor. 4. kn electrical distribution system-coin- :prising a conductor of substantial "len tli, and means tocool said conductor including a pluralityof isolated receptacles adapted to contain 011, said conductor having isolated portions thereof immersed in the cu in said rece tacles, and in heat-exchanging relation therewith; and means to abstract heat :"hom and causes circulation of cool oil about said immersed portionsof said conductor.

5. An electrical distribution system mom'- pris'ing a conductor of fixhstainti'fil length, oil immersed switches iri proximity-to said conductor and 'electrimillynud thermally connected therewith. and means to cool said conductor and switches in cl riding 'a plurality of receptacles adapted to contain o'il, swirl conductor having isolated portions thereof immersed inthe-di l in said receptacles and in heat exchang'ing relation with the oil, and means to abstract heat from the-oil in said receptacles, and cause a circulation of cool oil about the immersed portions of said conductor. I

6. An electrical -tlistribution system including an electric conductor of substantial length, said conductor also thermally-couductive throughout its lengthanillicatedby the current. carried-by it, and cooling means for said conductor compr'isingn plurality of isolated heat absorbent units in-thermal conncction therewith along its length toa lraw heat alonga-nd absorb heat from said conand means- '0 abductor, and means to dissipate the heat absorbed by said units.

7. An electrical distribution system. comprising an electric conductor of substantial length, said conductor also thermally-conductive throughout itslength, an oil immersed switch arranged in proximity thereto and electrically and thermally connected therewith, said system heated bythe current carried by it, and cooling means for the system comprising a, plurality of isolated, heat-absorbent units in thermal connection with said conductor along its length arranged to draw heat along and absorb heat from said conductor having means to dissipate the heat absorbed by them.

8. An electrical distribution system comprising a plurality of electrically-insulated parallel electric conductors of substantial length, said conductors also thermally-conductive throughout their lengths and heated by the current carried by them, and cooling means for said conductors comprising a plurality of independent heat-absorbent means, said conductors arranged in heat-exchanging relation with said heat-absorbent means, and each of said heat-absorbent means common to all of said conductors, and having means to dissipate the heat absorbed by them.

9. An electrical distribution system comprising a plurality of electrically-insulated parallel electric conductors of substantial length which are also thermally-conductive along their length and adapted to heat by the current carried them, and cooling means for said conductors comprising a plurality of independent receptacles adapted to contain an electrically-insulating, heat-absorbent fluid, as oil said conductors having isolated portions along their lengths immersed in the fluid in and insulated from said receptacles and in heat-exchanging relation with said fluid whereby the fluid will absorb the heat of said conductors, each receptacle being common to all. of said conductors. and said receptacles, having means to dissipate the heat absorbed by th fluid therein.

10. An electrical distribution system comprising a plurality of electrically-insulated parallel electric conductors of substantial length which are also thermally-conductive along their len h and adapted to heat by the current carrie by them, and cooling means for said conductors comprising a plurality of independent receptacles-adapted to contain an electrically-insulating. heat-absorbent fluid. as oil, said conductors having isolated portions along their lengths immersed in the fluid in and insulated from said re- -ceptacles and in heat-exchanging relation extension secured to said conductor the heat absorbed by the fluid in said receptacles and circulate cool fluid about said immersed. portions of said conductors comprising artificial cooling means for the fluid.

11. An electric conductor of substantial length also thermally-conductive along its length and heated by the current carried by it, having a plurality of localized, enlarged, heat-dissipating portions along its length. a

12. In combination, an electric conductor of substantial length also thermally-com ductive along its length and heated by the current carried by it, and cooling means for said conductor comprising means to draw the heat along the conductor to a plurality of isolated portions thereof and abstract heat from the conductor at such isolated portions and dissipate the heat abstracted.

13. The combination of an electric conductor of substantial length also thermallyconductive along its length and heated by the current carried by it having a lateral in thermal connection therewith, and means to cool said extension, thereby to extract heat from the conductor.

14. The combination of an electric conductor of substantial length also thermallyconductive along its length and heated by the current carried by ithaving a lateral extension secured in thermal connection therewith, and a receptacle adapted to contain oil in which said extension is immersed, and means to cool the oil thereby to cool the conductor.

15. In combination with an electric conductor of Substantial length also thermallyconductive along its length heated by the current carried by it, means to cool said conductor comprising a thermally-conducting conductor extension having substantial heatdissipating area arranged to draw heat along said conductor and dissipate the heat. and means thermally securing said extension to said conductor.

16. In combination with an electric mnductor of substantial length also thermallyconductive along its length heated by the current carried by it. means to cool said conductor comprising a thermally-conducting conductor extension. means securing it in thermal-conduction therewith. and artificial cooling means for said extension thereby to copl the conductor.

17. An electric conductor heated by the current carried by it having a plurality of localized heat dissipating portions to which heat is adapted to be drawn from intermediate portions of the conductor to be dissipated. thereby to maintain the conductor cool. and means to absorb heat from said localized portions of the conductor and dissipate the heat absorbed.

18. An attachment for an electric conducfor having substantial length and thermany-conductive along its length and hearted by the current carried by it, comprising :1 thermal condlnewt-extension adapted to be secured to the conductor in thermal-conilnction therewith, and a receptacle adapted to contain oil in which said extension is immersed having means to cool the oil in said receptacle, thereby to cool the conductor.

19. The method of cooling an electric con- 10 (luctor of Substantial length which isalso thermallywoniluctive along ilS lengllh whi h consists in abstracting heat from and cooling localized portions of lhe conrlnelor. thereby causing a flow of heat from the intermediate heated-portions thereof llrlillt'. localized cooled-portions, whereby to cool the entire conductor.

In testimony whereof. I have signed my name to this specification.

' GEORGE A. BURNHAM. 

